The invention relates to an electronic trip device comprising:
a processing unit having inputs to receive electrical signals representative of electrical quantities and an output to supply a tripping signal to a tripping relay, and
a man-machine interface connected to the processing unit to supply setting parameters and to display information and tripping curves on a screen.
The invention also relates to a circuit breaker comprising such a trip device.
Electronic trip devices of known types comprise man-machine interfaces to perform adjustment of the tripping parameter settings. The man-machine interfaces generally comprise screens for display of said setting parameters and display of values of electrical quantities, in particular the values of the currents flowing in the contacts of a circuit breaker. It is also known to use a keypad or buttons to select pre-established setting parameters, for example tripping function threshold or time delay parameters.
A trip device comprising a man-machine interface with a flat screen readout is described in particular in the Patents FR 2,654,539 and U.S. Pat. No. 5,220,479. In these documents the screen graphically displays the shape of the tripping curve, setting parameter indications, and current values.
Other circuit breakers comprising user interfaces with readout displays and keypad buttons are described in the U.S. Pat. Nos. 4,870,531 and 4,991,042.
However, known man-machine interfaces or user interfaces do not enable dependable setting parameter adjustment to be performed. Known interfaces generally use scrollable menus which do not give sufficient indication of the setting operations being performed.
The object of the invention is to provide a trip device comprising an improved man-machine interface enabling parameter settings to be adjusted or information to be displayed easily and dependably, and to provide a circuit breaker comprising such a trip device.
In a trip device according to the invention, the man-machine interface comprises means for displaying setting parameters which modify the visual aspect of at least one portion of curve representative of a parameter whose setting is being adjusted.
In a preferred embodiment, the means for displaying setting parameters modify the visual aspect of at least one portion of curve by increasing the thickness of said at least one portion of curve representative of a parameter whose setting is being adjusted.
Preferably, the means for displaying setting parameters frame at least one item of information displayed on the screen representative of a parameter whose setting is being adjusted.
Advantageously, the means for displaying setting parameters change at least a color of text or background of at least one item of information displayed on the screen representative of a parameter whose value is being modified.
In a particular embodiment, the man-machine interface comprises display means for displaying a scrollable menu to frame at least one item of information to be selected in a selection phase.
Preferably, the display means frame in a scrollable menu one item of information in the top-most position, one item of information in the bottom-most position, and items of information scrolled in a frame in a fixed intermediate position between a top-most position and a bottom-most position.
In a preferred embodiment, the man-machine interface comprises selection means comprising function buttons associated to indicator lights to indicate a function selected by a button.
Advantageously, the function buttons comprise at least a first button to select a measurement function, at least a second button to select a maintenance function, and a third button to select a setting function.
Preferably, the parameters of a trip device according to an embodiment of the invention are set according to a process comprising:
a step involving pressing on a setting function selection button,
a step involving display of a list of protection curves,
a step involving pressing on at least one shift button in a scrollable menu,
a step involving pressing on a validate button to select a curve whose parameters are to be set,
a step involving display of a selected curve and of corresponding setting parameters,
a step involving display of a selected portion of curve with broader thickness and of a corresponding parameter with a frame,
a step involving pressing on at least one shift button to change the portion of curve and the corresponding parameter,
a step involving pressing on a validate button to switch to parameter value modification mode,
a step involving pressing on a shift button to change parameter values, and
a step involving pressing on at least one validate button to quit modification mode.
A circuit breaker according to the invention, comprising main contacts connected in series with power conductors, current sensors arranged on said conductors, and a tripping relay receiving a tripping signal to bring about opening of said contacts, comprises a trip device as defined above connected to said current sensors and to said tripping relay.